1. Field of the Invention
The present invention relates to a starting element such as can be used, for example, within a drivetrain of a motor vehicle.
2. Description of the Related Art
In many motor vehicles, i.e., for example, passenger cars, trucks, utility vehicles, tractors and other corresponding engine-operated vehicles, a drive motor is used for driving one or more driven wheels. A drivetrain of a motor vehicle of this type accordingly comprises the above-mentioned drive motor and additional components as the case may be. A drivetrain of this kind can comprise, for example, a shiftable transmission which provides a plurality of transmission ratios so that it is possible to adapt the torque supplied by the drive motor or the rotational speed thereof by a corresponding selection of a gear and the transmission ratio associated with this gear.
Starting elements by which the drive motor can be temporarily completely or at least partially decoupled from further components of the drivetrain, for example, are used to enable the drive motor to continue running also when a motor vehicle of the type mentioned above is stationary, which may be advisable, for example, under certain operating conditions with an internal combustion engine, i.e., for example, an Otto engine or a diesel engine. In this way, the drive motor can continue running without rotational movement of the driven wheel or driven wheels.
A starting element can operate, for example, based on a hydrodynamic torque converter or also based on a frictionally engaging clutch to name only two examples of corresponding starting elements. In torque converters, which may also include a friction clutch, for example, a wet multiple plate clutch, for bypassing the actual torque converter, for example, but also in wet clutches, a liquid can be provided in the interior of a starting element of this kind, for example, for transmitting power, for cooling, for lubrication or for other purposes. Depending on the specific design, it may be possible, for example, to improve a cooling behavior of a clutch of this kind so that installation space can possibly be saved. Moreover, it may also be possible through the use of corresponding hydraulic liquids to actuate a wet multiple plate clutch of this type also by means of a hydrodynamic piston.
In torque converters and other wet multiple plate clutches, so-called piston jets, diaphragms, chokes or other flow limiters in conjunction with a piston of this kind are sometimes used and, depending on the design of a starting element of this kind, can ensure or increase the functionality of the respective clutch. For example, DE 10 2009 045 609 A1 describes a torque transmission system which can be used for a vehicle with a transmission in which a plurality of nozzle orifices are implemented in a corresponding piston.
These nozzle orifices are often arranged in the piston itself by drilling processes. This process is often time-consuming and, further, can lead to contamination, for example, by drillings and other contaminants occurring during machining. Because of these impurities and contaminants, subsequent time-consuming cleaning of the piston in question may sometimes be advisable or possibly even necessary in order not to risk impairing the functionality of the starting element.
Tangential leaf springs, for example, are also used in torque converters. The piston is arranged at a housing cover of the torque converter in question by means of these tangential leaf springs. DE 198 81 000 B4, for example, describes a corresponding torque converter. In order to make it possible to mount the tangential leaf springs, openings are provided at the piston so as to be distributed along the circumference. These openings are used during the assembly process to rivet the tangential leaf springs to the cover by means of a riveting tool reaching through the openings. They can also be screwed or welded to the cover, for example, by using other corresponding tools. After this process, they are tightly closed, which can be accomplished, for example, by plugs. Also, special seals can be provided or sealing disks can be used. In these constructions, all of the openings are completely sealed for the purpose of ensuring functionality.